Moscow
— Diplomatic signals have begun to fly thick and fast between the Kremlin and the incoming Reagan administration in Washington. Both sides are going out to their way to sound positive and forthcoming.

But, Western diplomats here warn, it is too early to make firm conclusions. "No one should be lulled," says one source. "There's no sign yet that the Soviets are prepared to make any real concessions at all, on strategic arms, in Afghanistan, or anywhere else."

The latest set of signals was exchanged via the incoming chairman of the Senate Foreign Relations Committee, Sen. Charles Percy (R) of Illinois. The Kremlin made clear its enormous curiosity about Mr. Reagan and the new Senate with its Republican, conservative majority. Senator Percy had been briefed by Mr. Reagan himself before arriving here.

On the surface, the Percy visit went well. He spent 2 1/2 hours with Leonid Brezhnev himself Nov. 26, and he saw Defense Minister Dmitri Ustinov Nov. 27. He thus became the first American to talk with the influencial minister since Us Defense Secretary Harold Brown saw him at the Carter-Brezhnev summit in June 1979.

After the Brezhnev meeting, Senator Percy said the Soviet leader had made "certain assertions" that led Percy to believe there was "hope" for US-Soviet relations. He spoke of a "positive" meeting that raised many issues in a "frank" way.

The senator was satisfied that "we are getting to better understand each other." Standing beside him, US Ambassador Thomas Watson added that he had found the meeting "exciting" because it had "moved the ball upward a little."

The Soviet news agency Tass said Mr. Brezhnev had denied that Moscow had started a new arms race, and had said the need now was for "political will" and a "well-considered, realistic policy." The Soviet Union did not want any worsening of ties with the US. It did not want what had been achieved by joint efforts in earlier years to be "thrown back."

In a direct reference to President-elect Reagan's campaign speeches, Mr. Brezhnev, according to Tass, "stressed the hopelessness of attempts to achieve military superiority over the USSR."

There should be "no stagnation" to efforts to limit strategic arms, Tass cited Mr. Brezhnev as saying.

Tass gave no indication that Mr. Brezhnev was ready to renegotiate the SALT II treaty, now blocked in the Senate. One widely mentioned idea is that Mr. Reagan will suggest taking the principles behind Salt II and merge them with SALT III talks on missiles in Europe and other issues, using that as the basis for new talks.

Mr. Brezhnev did not mention that in the Tass report -- not did he say that the US had to talk SALT II as it stands. In fact, he has not said that since Nov. 4. Nor have other senior officials.

all this was in line with what the Soviets had been saying since Mr. Reagan was elected on Nov. 4.

Moscow has asked Mr. Reagan for "constructive steps." Mr. Brezhnev himself said in the Kremlin Nov. 17 that any such constructive steps would meet a "possitive response" from the USSR.

In public Moscow does not accept that the SALT II treaty now has no hope of being ratified in the Senate. Unofficially, in meetings with US visitors Soviet officials have been keenly interested in US ideas for new SALT talks.